1. Field of Invention
The present invention relates to a wrench equipped with a torque-setting mechanism and, more particularly, to a wrench equipped with a lockable torque-setting mechanism.
2. Related Prior Art
Wrenches are used to exert torque on fasteners such as threaded bolts and nuts to fasten work-pieces. It is important to exert a proper value of torque. In some applications, it is particularly important to have the value of torque close to but under a limit to effectively fasten the work-pieces without the risks of damaging the work-pieces.
Some wrenches are equipped with torque-setting mechanisms. Such a torque-setting mechanism is used to set a maximum value of torque that can be exerted via such a wrench. A typical torque-setting mechanism includes a knob connected to a handle of a wrench. The maximum value of torque is set by rotating the knob relative to the handle. The knob might however be accidentally rotated relative to the handle in operation.
In another conventional torque-setting mechanism, the knob is formed with teeth for engagement with teeth formed on the handle. The knob can be translated relative to the handle between two positions. In the first position, the teeth of the knob are engaged with the teeth of the handle so that the knob cannot be rotated relative to the handle. In the second position, the teeth of the knob are disengaged from the teeth of the handle so that the knob can be rotated relative to the handle. The knob might however be excessively translated and hence removed from the handle.
In another conventional torque-setting mechanism, a spring-biased detent is connected to the knob and a recess is made in the handle. The spring-biased detent is intended for insertion in the recess to keep the knob connected to the handle. The insertion of the spring-biased detent in the recess has however been proven to be ineffective to keep the knob connected to the handle.
In another conventional torque-setting mechanism as disclosed in Taiwanese Patent M371616 issued to the present applicant, the handle is made with an adequate length to keep the knob connected to the handle should the spring-biased detent be removed out of the recess again. The long handle is however unreliable.
Therefore, the present invention is intended to obviate or at least alleviate the problems encountered in prior art.